2011 - Repozytorium publikacji - Politechnika Gdańska

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Publikacje z roku 2011

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Chemical and biological stability of polyene macrolides
- Natalia Salewska
- Joanna Boros-Majewska
- Maria Jolanta Milewska
- Sławomir Milewski
2011 Acta Biochimica Polonica
The polyene macrolide antibiotics have been used in an-tifungal therapy since first o f them were discovered in 1950's. Up to now, four polyene macrolides are being used in medical practice, namely amphotericin B, nystatin, candi-cidin and pimaricin.The antifungal activity and mode of ac-tion of polyene macrolides is determined by their structure, chemical and physical properties.The main fragment of polyene macrolide molecule is the macrocyclic ring built of two different regions. One fragment is hydrophobic, where an unsaturated polyene chromophore is located and on the other side a number of hydroxyl groups and "polar head" constitute a hydrophilic region. The number of conjugated double bonds in the chromophore determines a characteristic UV absorption spectra of the molecule which is represented by three peaks. According to that, amphotericin B and candicidin are both classificated as heptaenes, while nystatin as tetraene or a "degenerated heptaene". This multifunctional and large ring structure of the antibiotics causes many prob-lems in everyday usage. They are very poorly soluble in water, and can easily form aggregates in aqueous media. Polyene antibiotics exhibit also poor stability to heat, UV radiation and extremes of pH. As solids they are relatively stable but in aqueous solution, stability is much lower.In our work we examined the stability of three macrolides: amphotericin B, candicidin and nystatin complex from different sources. Our research was focused on structural changes induced by different factors like temperature, pH, solvents or exposition to light and UV radiation. We re-lated results of physico-chemical experiments to biological activity of this antifungal agents, to compare which envi-ronmental factor have the most influence on antimicrobial activity. The physical and chemical damages where studied by absorption spectroscopy and HPLC analysis conjugated with mass spectrometry. The results showed that nystatin is the least stable compound in the series and the exposition to different environment factors cause the conformational modifications that effect in lower biological activity.
Chemical Quality of Bottled Waters: A Review
- Malwina Diduch
- Żaneta Polkowska
- Jacek Namieśnik
2011 Pełny tekst JOURNAL OF FOOD SCIENCE
Bottled water has become very popular for quenching thirst and as a dietary (mineral) supplement. Theplethora of natural mineral waters precludes any unequivocal system of classification, which makes it difficult for theconsumer to choose a water with properties that suits him/her exactly. The ever-increasing popularity of bottled watersmeans that it is of the utmost importance to determine not only their mineral content, but above all, the content ofpossible contaminants, especially organic ones. In this respect bottled waters are a special case, because apart from organiccontamination from the environment, the water may become secondarily contaminated as a result of its being improperlytransported and stored. Pesticides, volatile organic compounds, and carbonyl compounds have been detected in samplesof bottled water. This overview shows the available published information on levels of inorganic constituents and organiccontaminants in samples of bottled water in the context of sample preparation procedures and analytical techniques.
Chiral gas chromatography as a tool for investigation into illicitly manufactured methamphetamine
- Calum Morrison
- Frank Smith
- Tomasz Tomaszewski
- Karolina Stawiarska
- Marek Biziuk
2011 CHIRALITY
W pracy przedstawiono zastosowanie gazowej chromatografii chiralnej do rozdzielania związków ubocznych powstających w trakcie syntezy metylamfetaminy. Opisano rozdzielanie enancjomerów efedryny, pseudoefedryny, chlorowanych związków posrednich i metylamfetaminy stosując do derywatyzacji bezwodniki fluorowanych kwasów. Jako fazę chiralną zastosowano CHIRALDEX B-DM. Do rozdzielenia enancjomerów pseudoefedryny oraz chlorowanych produktów pośrednich stosowano derywatyzację bezwodnikiem kwasu pentafluoropropionowego (PFPA), a do rozdzielania enancjomerów efedryny stosowano do derywatyzacji bezwodnik kwasy tetrafluorooctowego (TFAA). Czas rekacji wynosił 40 min. Zbadano również możliwość zastosowania do derywatyzacji bezwodnika kwasu heptafluoromasłowego.
Chitosan, Collagen and Gelatin in the design of novel materials with antimicrobial acticity
- Grzegorz Gorczyca
- Robert Tylingo
- Piotr Szweda
2011 Acta Biochimica Polonica
Medical devices containing and releasing antiinfective agents directly on the site of injury are a common group of materials available and widely used in treating difficult to heal wounds. Sustained contact of the active agent to the damaged tissue, needed to inhibit infection and preservation of microbiological purity of the wound, is provided by the immobilization antimicrobial agents on the surface of the matrix material or by providing controlled release profile from its interior.Use of natural polymers such as collagen and chitosan allows materials to receive similar properties to the extracellular matrix. The advantage of this type of materials is also their biocompatibility, no toxicity and low propensity to cause allergic reactions. The colourless and odourless collagen from the fish skins, can be isolated in a high yield by an exhaustive extraction of the organic acids. Chitosan is produced commercially by deacetylation of chitin, which is the structural element in the exoskeleton of crustaceans and cell walls of fungi. Both of them are commonly used in a large-scale production of many applications.Recently we have developed several biopolymer spongy systems designed for release of antimicrobial peptides such as lysostaphin, which have appropriate texture profile and other properties for modern medical wound dressings. Lysostaphin is a zinc metalloproteinase that degrades the cell wall of almost all known staphylococcal species. As a result of modifications in both the matrix composition and concentration of crosslinking agent a number of materials with different absorption, solubility and texture parameters were received. This is especially valuable when designing systems for the controlled supply of chemotherapeutics at the site of injury. Control of composition and concentration of crosslinking agent allows to control the rate of release of immobilized peptide inside the matrix, depending on the speed of its degradation, and diffusion kinetics.
Chladni and circular saw disc vibrations visualisation
- Lubomir Javorek
- Kazimierz Orłowski
2011
In this paper are described some methods for saw disc vibration monitoring in march of time (chronology). Ernst Chaldni, the father of sound visualisation and his patternsis are mentioned. In the last partof article are introduced results received with authors measuring systems.
Chlorido(η5-cyclopentadienyl)- [(4a,4b,8a,9,9a-η)-fluorenyl](fluorenylκC9)zirconium(IV) toluene solvate
- Agnieszka Łapczuk-Krygier
- Łukasz Ponikiewski
- Jerzy Pikies
2011 Pełny tekst ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE
Tematem publikacji jest kompleks zyrkonu z ligandami fluorenylowymi. Otrzymany związek uzyskano w postaci monokrystalicznej i przy pomocy rentgenowskiej analizy strukturalnej wyznaczono strukturę tego związku.
Chosen aspects of muscle biomechanics
- Wiktoria Wojnicz
- Edmund Wittbrodt
2011
Considering a striated skeletal muscle as a different properties mechanical system, one can understand series of important phenomena happening in a real muscle phenomenon of muscle: 1) force delivery to skeletal apparatus through tendons; 2) changing of exerted muscle belly mass distribution with regards to skeletal apparatus; 3) beginning drop of muscle force. A disregard of first phenomenon causes an impossibility to explain why different forces are occurring in the distal tendon and the proximal tendon. Considering the second phenomenon, one can estimate influence of muscles' bellies inertial forces on rotation dynamics of limb examined. An existence of third phenomenon can be explained by modeling a muscle as a rigid-flexible system consisted of different mechanical properties fragments. Numerical results of three mechanical models of muscle behavior are presented in this paper. Each mechanical model has eighteen forms. Each form has two mathematical formulation: the differential equations system and the integro-differential equation. This method of modeling allows to consider muscles with tendons (stiff systems) or muscles without tendons (non-stiff systems). The behavior of fifty four forms were examined using a complex concentric-excentric-isokinetic exertion. Analyzing numerical results, one can conclude in what cases respective mechanical model might be used.
Chwilowe skoki ciśnienia w pompie tłoczkowej z rozrządem krzywkowym- analiza i badania
- Piotr Patrosz
2011
artykuł opisuje zjawiska pojawiające się w prototypowej pompie tłoczkowej o zmiennej wydajności z rozrządem krzywkowym. zjawiskami tymi są chwilowe skoki ciśnienia w komorach roboczych pompy. opisywane zaburzenia negatywnie wpływają na pracę urządzenia, ograniczając jego dopuszczalne parametry eksploatacyjne. w artykule przedstawiono wyniki badań oraz analiz tych zjawisk, a także zaproponowano rozwiązanie kompensujące niekorzystne zjawiska.
Ciągły pomiar geometrii rozjazdów kolejowych
- Zbigniew Kędra
2011 Pełny tekst Przegląd Komunikacyjny
W artykule opisano zasady przeprowadzania pomiarów szerokości toru i żłobków na podstawie obowiązujących przepisów na liniach kolejowych w Polsce I Niemczech. Następnie omówiono metodykę wykonywania pomiarów ciągłych szerokości toru i różnicy wysokości toków szynowych w rozjazdach kolejowych z wykorzystaniem toromierza elektronicznego TEC1435. Szczególną uwagę zwrócono na powtarzalność wyników pomiarów w miejscach nieciągłości toków szynowych.
Ciekawe i niezwykłe eksperymenty fizyczne
- Andrzej Kuczkowski
2011
w pracy zaprezentowano szereg eksperymentów z różnych działów fizyki (mechanika, elektryczność, optyka), które mogą zainteresować i zainspirować wielu odbiorców. W przypadku eksperymentów pokazowych na ich percepcję wpływa nie tylko ich potencjał informatyczny, ale też sposób ich prezentacji a przede wszystkim umiejętność rozbudzenia zaciekawienia u słuchaczy.
Cienie, cykl 'Odcinki' (1998)
- Krzysztof Wróblewski
2011
Katalog aukcji polskiej sztuki współczesnej, która odbyła się w Domu Aukcyjnym Desa Unicum w Warszawie w dniu 15 grudnia 2011 roku. Katalog liczy 62 strony i zawiera noty biograficzne artystów wraz z charakterystyką twórczości w jezyku polskim, i zawiera 59 kolorowych reprodukcji (rep. autora s. 12). Wydawcą katalogu jest Desa Unicum.
Cmentarz-ogród w urbanistyce XIX i XX wieku
- Katarzyna Rozmarynowska
2011
Autorka artykułu analizuje przyczyny pojawienia się w miastach dziewiętnastowiecznych cmentarzy parkowych; przedstawia ich typologię. Analizuje także zjawisko przekształcania nieużytecznych cmentarzy w parki. Wywód ilustruje przykładami z terenu Francji, Anglii, Niemiec, Ameryki oraz Gdańska.
CMOS Low-Dropout Regulator With Improved Time Response
- Grzegorz Blakiewicz
2011
Przedstawiono nową konfigurację regulatora o obniżonym spadku napięcia, w którym wykorzystano stopień wyjściowy z równoległym sprzężeniem napięciowym. Dzięki obniżonej rezystancji wyjściowej stopnia, uzyskano poprawę odpowiedzi impulsowej regulatora na szybką zmianę prądu wyjściowego.
CMOS realisation of analogue processor for early vision processing
- Waldemar Jendernalik
- Jacek Jakusz
- Grzegorz Blakiewicz
- Robert Piotr Piotrowski
2011 Pełny tekst Bulletin of the Polish Academy of Sciences-Technical Sciences
The architecture concept of a high-speed low-power analogue vision chip, which performs low-level real-time image algorithms ispresented. The proof-of-concept prototype vision chip containing 32 × 32 photosensor array and 32 analogue processors is fabricated usinga 0.35 μm CMOS technology. The prototype can be configured to register and process images with very high speed, reaching 2000 framesper second, or achieve very low power consumption, several μW. Finally, the experimental results are presented and discussed.
Coatings for improvement of high temperature corrosion resistance of porous alloys
- Sebastian Molin
- Maria Gazda
- Piotr Jasiński
2011 JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
Porowate stopy metaliczne są potencjalnymi podłożami nośnymi dla tlenkowych ogniw paliwo. Ich stosowanie obniża cenę ogniw paliwowych, co zaowocuje ich szybszą komercjalizacą. Jednak są one podatne na korozję w wysokich temperaturach. Dotychczas brak jest metod, które mogą poprawić rezystancję korozyjną porotawych stopów w wysokich temperaturach porowatych stopy do zastosowań SOFC. W tym artykule zaproponowano sposób na poprawę odporności na korozję stopów porowatych. Powłoki ochronne są przygotowywane przez nasączanie prekursorów polimerowych, które zawierają kationy Y.
Cohousing: the place of community
- Robert Idem
2011
The crisis of social bonds, which affects living environment, has lead to the revival of traditional neighbourly relations. The idea of cohousing is included in this trend. Its inspiration may be found in the tradition of rural community, which used to adjust the system of rural settlements to the needs of community life.
Collection Efficiency in Narrow Electrostatic Precipitators with a Longitudinal or Transverse Wire Electrode
- Anna Niewulis
- Janusz Podliński
- Jerzy Mizeraczyk
- Volodymyr Shapoval
2011 IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
Recently narrow electrostatic precipitators (ESPs) have become a subject of interest because of their possible application in diesel engine exhaust systems. In this work, results of particle collection efficiency measurements in narrow electrostatic precipitators for negative and positive dc voltage polarity are presented. The ESP usedin this work was a parallelepiped equipped with wire discharge electrode and two collecting plate-electrodes. The experiments were carried out for two discharge electrode positions: longitudinally or transversely to the main flow direction. The obtained results showed that the collection efficiency strongly depends on the discharge electrode position. It is higher in the ESP with longitudinally-to-flow placed discharge electrode. The collection efficiency is also influenced by the EHD secondary flow generated in the ESP. The EHD secondary flow with high migration velocity (y-component of the particle velocity) and low turbulence intensity increase the chanceof the particle deposition on the collecting electrodes.
Collective Uncertainty Entanglement Test
- Łukasz Rudnicki
- Paweł Horodecki
- Karol Życzkowski
2011 PHYSICAL REVIEW LETTERS
For a given pure state of a composite quantum system we analyze the product of its projections onto aset of locally orthogonal separable pure states. We derive a bound for this product analogous to theentropic uncertainty relations. For bipartite systems the bound is saturated for maximally entangled statesand it allows us to construct a family of entanglement measures, we shall call collectibility. As thesequantities are experimentally accessible, the approach advocated contributes to the task of experimentalquantification of quantum entanglement, while for a three-qubit system it is capable to identify thegenuine three-party entanglement.
COLREGS compliance in Evolutionary Sets of Cooperating Ship Trajectories
- Rafał Szłapczyński
- Joanna Szłapczyńska
2011 Pełny tekst Reliability: Theory & Applications
In general, Evolutionary Sets of Cooperating Ship Trajectories combine some of the assumptions of game theory with evolutionary programming and aim to find optimal set of cooperating trajectoriesof all ships involved in an encounter situation. In a two-ship encounter situation the method enables the operator of an on-board collision-avoidance system to predict the most probable behaviour of atarget and to plan the own manoeuvres in advance. In a multi-ship encounter the method may be used to help an operator of a VTS system to coordinate the manoeuvres of all ships. The improvement presented here is a new way of modelling some of the COLREGS rules. Due to thischange, the method is now able to find solutions, which are more compliant with COLREGS, more intuitive and consequently - safer from the navigator's point of view. The paper contains a detaileddescription of collision-avoidance operators used by the evolutionary method and simulation examples of the method's results for digital maps.
Combined method of multibeam sonar signal processing and image analysis for seafloor classification
- Andrzej Stepnowski
- Zbigniew Łubniewski
2011
The combined approach to seafloor characterisation was investigated. It relies on calculation of several descriptors (parameters) related to seabed type using three types of multibeam sonar data obtained during seafloor sensing: 1) the grey-level sonar images (echograms) of seabed, 2) the 3D model of the seabed surface which consists of bathymetric data, 3) the set of time domain bottom echo envelopes received in the consecutive sonar beams. The proposed method has been tested using field data records acquired from several bottom types in the Gulf of Gdańsk and the promising results have been reported. This paper presents and discusses several processing techniques of the calculated descriptors in the context of their use in seafloor classification. In particular, calculations of the standard deviation of the descriptors for small subsets of data and the application of the Principal Component Analysis procedure (PCA) were investigated.